The significant idea of the bilaterian body plan is directionality. By moving from a radial (circle) to a bilateral (line) symmetry, life transitioned from a passive state of “being” to an active state of “doing.”
Bilaterian Split: The Origin of Agency Read More »
Before, during, and after the K–Pg extinction: a thriving Late Cretaceous world of dinosaurs, pterosaurs, birds, and flowering plants gives way to the asteroid strike and global collapse that ended the age of non-avian dinosaurs.
The K-Pg Extinction Read More »
The Cenozoic era starts with the K–Pg extinction 66 million years ago. That event marks the sudden end of the reign of dinosaurs and the rise of mammals and birds.
Cenozoic Era: Age of Mammals & Birds Read More »
The Mesozoic era starts with the end-Permian mass extinction 252 million years ago. Dinosaurs ruled over all, including us. It ends the reign of dinosaurs with the K–Pg extinction 66 million years ago.
Mesozoic Era: Age of Dinosaurs Read More »
The start of the Paleozoic era is marked by burrowing life 538.8 million years ago. The era includes the dominant rise of our ancestors. It ends 252 million years ago with the end-Permian mass extinction, a volcanic cascade global warming event.
Paleozoic Era: The Age of Synapsids Read More »
Pteranodon was one of the great soaring pterosaurs of the Late Cretaceous, but it was only one branch in a much larger pterosaur story.
Pteranodons Emerge Read More »
The last pterosaurs were not all the same, and they were not simply faded leftovers.
The Last Pterosaurs Read More »
Pterosaurs were the first vertebrates to conquer the air, evolving a unique “finger-wing” anatomy that allowed them to dominate the skies for 160 million years.
Pterosaurs Diverge From Dinosaur Ancestors (within Ornithodira) Read More »
LCA of crocodiles and birds — the larger archosaur branch that later gave rise to crocodilians, pterosaurs, dinosaurs, and birds.
Archosauria Diverge Within Reptiles Read More »
Pterosaurs were the first vertebrates to achieve powered flight, but they were not dinosaurs.
